#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>

int main() {
	long long arr[10] = { 0 };
	long double sum = 0;
	for (int i = 0; i < 10; i++) {
		scanf("%lld", &arr[i]);

	}
	for (int i = 0; i < 10; i++) {
		sum += arr[i] / 10.0;
	}
	printf("%llf\n", sum);
	return 0;
}